What was Heinrich Mueller, a former head of the Gestapo, doing telling his CIA interrogators that the Spanish Flu came from the United States and that the Americans were therefore to blame? Didn't his CIA interrogators know this piece of information already if presumably the CIA were part of the cover-up?

Come on, this doesn't add up.

Heinrich Mueller also claims that the Spanish Flu was released accidentally and this would therefore imply that the release of the virus during WWI was entirely co-incidental. How can we take his word for this? Could it not for example have been a German agent who was responsible for 'accidentally' releasing the virus from a US lab?